Аннотация:Ribosomes are ribonucleoprotein nanoparticles responsible for the synthesis of all proteins in living cells. The function of a ribosome is to translate the genetic information encoded in the nucleotide sequence of mRNA into the amino acid sequence of a protein. During this process, the ribosome performs the unidirectional driving of a single mRNA chain and numerous mRNA-bound tRNA macromolecules through itself. In this process, the free energies of the transpeptidation reaction and GTP hydrolysis are consumed. Thus, the translating ribosome can be considered as a conveying protein-synthesizing molecular machine (Spirin 2002, 2004, 2009a; Frank & Gonzalez 2010). The purpose of this chapter is to analyze the conveying mechanism of this machine.
Subdivision of the Ribosome into Two Unequal Subunits
At first approximation, the ribosome can be described as a compact, almost spherical body with linear dimensions of 25 to 35 nm (reviewed in Spirin 1999, pp. 50–51). Detailed structural analyses reveal the highly complex, asymmetric quaternary structure of the ribosome (Ban et al. 2000; Wimberly et al. 2000; Harms et al. 2001; Yusupov et al. 2001; Ramakrishnan 2002; Gao et al. 2003; Schuwirth et al. 2005; Selmer et al. 2006).